1. Field of the Invention
The present invention is related to a pressure sensor for a vehicle and a brake fluid pressure control apparatus for a vehicle equipped with the pressure sensor.
2. Description of the Related Art
In a brake fluid pressure control apparatus for a vehicle that controls the brake fluid pressure applied to vehicle brakes, an electronic control unit controls various parts provided in fluid passages based on the pressure of brake fluid measured by a pressure sensor.
A conventional pressure sensor includes a sensing element 10 for measuring the pressure of brake fluid in fluid passages, a sensor housing 20 for accommodating the sensing element 10 and a contact probe 630 that is electrically connected to the sensing element 10 at one end thereof and is electrically connected to the electronic control unit 300 at the other end thereof (disclosed in unexamined Japanese patent application publication No. 2002-542107, paragraphs 0015 and 0016, and FIG. 1).
The conventional contact probe 630 includes a sleeve 631, a coil spring 632 housed in the sleeve 631, a rod 633 inserted into the sleeve 631. The sleeve 631 and the rod 633 are pressed by the pressing force of the coil spring 632 in the direction of their elongation.
The contact probe 630 is slidably inserted into an insertion hole 22c formed at a top end part of the sensor housing 20. The sleeve 631 and the rod 633 are elongated by the pressing force of the coil spring 632 so that the rod 633 is pressed to a connection part 11a of the sensing element 10 and the sleeve 631 is pressed to a connection part 302 of the electronic control unit 300.
In the contact probe 630, the sleeve 631 is pressed to the connection part 302 of the electronic control unit 300, whereby the contact probe 630 and the electronic control unit 300 are electrically connected. In this configuration, because the contact probe 630 is not fixed to the electronic control unit 300, the pressure sensor and the electronic control unit 300 can be easily connected or disconnected.
In the conventional pressure sensor, because the contact probe 630 is slidably disposed in the insertion hole 22c of the sensor housing 20 and the position of the contact probe 630 is not securely fixed, contamination, which is adhesion of dust between the sensing element 10 and the contact probe 630, may be caused by the influences of environment around the sensing element 10 or the sliding of the contact probe 630, which causes a problem that it is difficult to improve the reliability of the connection in the long term.
In the conventional pressure sensor, the rod 633 is pressed to the connection part 11a of the sensing element 10 and the sleeve 631 is pressed to the connection part 302 of the electronic control unit 300. Thus, the electrical connections at both ends of the contact probe 630 are contact connection, which causes a problem that the contact resistance is increased.
There has been another problem that positioning of the contact probe 630 in the sensor housing 20 is difficult because the contact probe 630 is slidable in the insertion hole 22c of the sensor housing 20.